1. Field of the Invention
This invention generally relates to barbecues including both portable and nonportable gas barbecues.
2. Description of Related Art
Gas fired barbecues have become very popular. A gas barbecue generally comprises a housing or cabinet that supports a grill over a combustion chamber. A burner in the combustion chamber attaches to a gas bottle as a fuel source. The popularity of these gas fired barbecues as an alternative to charcoal barbecues stems from ease of use, the elimination of ash disposal and minimal cleaning requirements after each use.
A number of particularly desirable features for charcoal and gas fired barbecues have evolved over the last several years. For example, charcoal barbecues produce relatively even heating over a cooking area by the proper distribution of charcoal briquettes in a combustion chamber. Burners in gas fired barbecues, on the other hand, act as localized heating sources requiring some structure for distributing the heat before it reaches the food being cooked. In both charcoal and gas fired barbecues it also important that the combustion chamber operate reliably in a variety of wind conditions.
Propane is often the fuel of choice for gas fired barbecues. Gas bottles under high pressure usually connect to a regulator that reduces the pressure and controls gas flow to the burner within the barbecue. This connection should facilitate the replacement of gas bottles. In portable barbecues it is important that the regulator and gas bottle be easily detached from the barbecue to facilitate storage within the barbecue. Portable barbecues also require some mechanism for positioning the housing above any supporting surface, particularly a combustible surface or one susceptible to heat damage. Each of these areas has been the subject of prior art development directed to the design of effective barbecues particularly gas-fired, portable barbecues.
For example, the following patents disclose diverse combustion chamber structures that seek to produce even distribution of heat:
______________________________________ 806,745 (1905) Koneman 1,885,325 (1932) Bogley 2,180,325 (1939) Dunning et al. 4,403,597 (1983) Miller 4,703,746 (1987) Hitch 5,172,682 (1992) Luebke et al. 5,211,105 (1993) Liu ______________________________________
The Koneman patent discloses a grill to be positioned over a heat source. The grill has a perforated flat bottom heat distributing diaphragm, a first corrugated diaphragm spaced above the heat distributing diaphragm and a similar, second corrugated diaphragm above the first corrugated diaphragm. The corrugations in each of the first and second diaphragms align. The corrugation peaks in the first diaphragm and valleys in the second corrugated diaphragms have offset apertures. Heat distributes from the bottom diaphragm through the first and second diaphragms to cook food that the second diaphragm supports. Fat from the food drips through the apertures in the valleys of the second corrugated diaphragm and into the first corrugated diaphragm to be carried away.
In the Bogley patent a broiler plate for use in a fry pan comprises a corrugated-like surface with apertures. The apertures allow heat to reach the food being broiled and allow juices from the food to pass through the plate to the pan.
A griller in the Dunning et al. patent has gas-fired heating elements and two spaced, parallel firebrick slabs. A lower slab and supporting plate have aligned apertures containing burner nozzles. The upper slab has apertures that are offset with respect to the apertures in the lower slab. The slabs are inclined with respect to the horizontal so fat dripping from material being cooked is collected in a drip sill.
The Miller patent discloses a heat transfer device in the form of a solid cast iron plate with an irregular top surface resembling a lava bed and a plurality of holes permitting the passage of fats and juices from any food being cooked. The areas around the openings are inclined toward the openings to promote the flow from food juice droplets through the openings.
In the Hitch patent an adjustable shutter grate for a barbecue comprises two parallel, stacked structures for controlling flare ups. Each structure has apertures, and the structures are slidable between two positions relative to each other. In one position the apertures align to provide a direct path from food being cooked on top of the structure to the heat source. In the other extreme position the apertures are completely blocked.
The Luebke et al. patent discloses a commercial convection cooker that includes a plurality of spaced plates with offset apertures. These apertures provide offset air passages for facilitating cooking.
In the Liu patent a smokeless and scorchless grill pan includes an upper food plate and an oil pan placed under the food plate. A fire heats the oil pan and the air in a hollow space between the oil pan and the food plate. The oil pan is corrugated with a plurality of apertures for passing heated air and two opposite recesses near a circumferential edge. The food plate is also corrugated and has a plurality of oil holes for allowing oil exiting the food to drop onto the oil pan and then to the opposite recesses of the oil pan.
Although each of the foregoing references disclose structures that distribute heat in cooking devices, only the Koneman, Bogley, Miller, Hitch and Luebke patents are applicable to barbecues. The Koneman and Dunning et al. patents disclose structures in which the support surface for food being cooked is slanted. The Koneman, Bogley, Hitch, Luebke and Liu patents disclose structures in which an upper corrugated plate supports the food directly. The Miller patent discloses a single plate as a heat transfer distributor, but designs the plate so that a portion of any juices exuded from the food will pass into a combustion chamber. The Koneman patent requires water that is converted to steam. None of these references describe a structure for distributing heat in a way that minimizes the transfer of juices into a combustion chamber and yet provides a method for producing smoke from those juices that flavors the food being cooked.
Portable barbecues should be constructed with legs that position the barbecue in a stable manner above any supporting surface and that readily stow for transport. The following patents disclose various leg structures for positioning portable barbecues above support surfaces:
______________________________________ 2,928,385 (1960) Peplin 2,985,164 (1961) Imoto 3,503,324 (1970) Gmeiner 3,753,431 (1973) Koziol 4,257,388 (1981) McGuire ______________________________________
The Peplin patent discloses a portable grill with a fire basket and two leg members. The leg members detachably fasten to the fire basket.
In the Imoto patent a collapsible camp stove has detachable legs. The legs move from a storage position to be supported in exterior clips on the side portions of the stove.
The Gmeiner patent discloses a collapsible charcoal grill. Supporting leg portions located in a bottom exterior recess thereof are disposed on hinges and pivot around a lower lateral wall edge.
In the Koziol patent a portable grill includes a detachable propane cylinder. When it is desired to use the grill for cooking, a support frame is removed from the grill and foot members are extended along with a hook for supporting the propane cylinder.
A foldable barbecue grill disclosed in the McGuire patent includes pivoted legs at each corner of a barbecue frame. Spring clips adjacent each leg retain the legs in a storage position. Other clips formed on the frame limit the rotation of the legs to a supporting position where the legs splay outwardly.
Although each of these references discloses various leg structures used for supporting a portable grill, the Imoto, Peplin and Koziol patents disclose leg structures that must be detached from the portable barbecue to moved from a storage position to a supporting position. The Gmeiner and McGuire patents disclose leg structures that are formed integrally with a portable barbecue, but are mounted entirely exteriorly of the barbecue. None of these patents disclose legs that are located interiorly of the barbecue for storage and pivot outwardly to support the barbecue in a stable manner.